Screw-driving bit



May 19, 1925. 1,538,195

A. LEVEDAHL SCREW DRIVING BIT Filed 001;. 24, 1923 5' I #22 flue/2721 xellem dzdz Patented May 19, 1925.-

UNITED STATES PATENT OFFICE.

AXEL LEVEDAHL, OF AURORA, ILLINOIS, ASSIGNOR TO INDEPENDENT PNEUMATIC TOOL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

SCREW-DRIVING BIT.

Application filed October 24, 1923. Serial No. 670,403.

T 0 all whom it may conmwn:

Be it known that- 1, Axial. LEVEDAHL, a citizen of the United States, residing at Aurora, in the county of Kane and State of Illinois, have invented new and useful Improvements in Screw-Driving Bits, of which the following is a specification.

This invention relates to screw driving bits particularly adapted for use with portable electric and pneumatic drills or other devices for driving screws by power.

Oneobject of my invention is to make bits of sheet metal and thus permit the bits being rolled to the proper thickness, giving uniform size and strength throughout all parts of the bit, making stronger bits than machined ones.

Another object of my invention is to provide sheet metal bits with reinforced flanges brought to shape by simply forming or bending the sheet metal stock from which the bits are made.

A further object of my invention is to employ these reinforcing flanges also as a means to prevent the bits slipping off the heads of screws and thus enable the latter to be driven by power rapidly and without loss of time.

In making bits from sheet metal, the stock has a substantially even thickness and strength throughout, and thus the bits may have their ends ground when worn without altering the shape or strength of the bits, thereby lengthening the life of the same.

The invention has for its object to make the bits cheaply, and consists further in the matters hereinafter described and more particularly set forth in the appended claims.

In the accompanying drawings- Fig. 1 is a perspective view of a sheet metal bit of my invention in a holder;

Fig. 2 is a view showing the flat blank from which the bit of Fig. 1 is formed;

Fig. 3 is a top plan view of the blank with its side margins bent to provide the side flanges of the bit;

Fig. 4 is a side view showing my improved bit engaged with a round headed fillister screw;

Figs. 5, 6, and 7 are sectional views taken on lines 5-5, 6-6, and 77, respectively, of Fig. 4;

Fig. 8 is a flat blank for a sheet metal bit having its kert' engaging part formed for a button headed screw with a concave button to its kerf; I

8 in bit Fig. 9 shows the blank of Fig. form and engaging a screw of the type mentioned;

Fig. 10 shows a flat blank for a sheet metal bit having its lower end formed to engage the kerf in a regular flat head conntersnnk wood screw or similar machine screw; and i Fig. 11 shows the bit made from the blank of Fig. 10 and engaging the type of screw indicated.

To make a bit of my invention, I take a rolled strip of sheet metal, such as steel, and cut it into lengths, making flat blanks 1 of the size required, as shown in Fig. 2. The blank 1 has a substantially uniform thick ness, width and strength throughout with its top and bottom edges 2, 3 preferably straight and parallel, the former to lie in the top of the slot 4 of the holder 5 and the latter to engage against the bottom of the kerf 6 in the head 7 of a screw 8, as shown in Figs. 1, 4, and 5.

The side margins of the blank 1 are turned or bent to provide side flanges or lips 9, 9.- The dotted lines a. in Fig. l in dicate where the flanges 9 are turned and also the width of the kerf engaging portion of the bit, which in the instance shown is substantially equal to the length of the kerf so that the flanges 9, 9 lie outside of the head 7 of the screw. These flanges 9, 9. indicated in Figs. 1, 6, and 7, are turned to project on opposite sides of the main body part of the bit and when engaging a fillistcr screw head 7. as shown in the drawings. the flanges or lips 9, 9 extend to one side of the kerf 6 at the ends thereof and engage against the outer side face of the screw head. The flanges 9, as indicated in Figs. 6 and 7, are preferably given a curvature to conform to that of the screw head. so as to lie substantially against it, and projecting on opposite sides of the kerf 6 hold the bit from slipping ofl the screw head when engaged therewith. These flanges or lips 9, 9 extending the full length of the bit body 1 also reinforce the same and make itstronger to resist twisting.

To hold the bit 1 in the holder 5, any

takes the form of a cross pin or screw inserted. through the holder and bit, a hole 11 being made in the bit body near 'its upper edge for that purpose.

In makin a sheet metal bit of my invention for a button head screw, I form the blank as shown in Fig. 8. There the bit 12 is provided at its lower end with a curved edge 13 to conform to the concave curvature of the bottom wall of the kerf 14 in the but ton head 15 of the screw 16, as shown in Fig. 9. The bit 12 has side flanges 17, 17 formed in the same manner as the bit 1, only their lower ends are cut away so as to allow the curved edge 13 to project below the same. This bit 12 also has a hole 11 for the fastenin screw 10 in the socket or holder 5.

11 making a sheet metal bit of my invention for the regular or ordinar fiat head countersunk wood screw or simi ar machine screw, I fashion the blank as shown in Fig. 10. There the bit 18 has its lower'end portion formed to provide a flat tongue 19 having the same thickness as the bit 18, and of a shape to engage the kerf 20 in the head 21 of a regular countersunk wood screw or similar machine screw 22. The bit is provided with reinforcing side flanges 23, 23 and also has a hole 11 to receive the fastener 10 of the socket or holder 5. The side flanges 23,

23 terminate short of the ton ue 19, as shown in Fig. 10, and this is provided by cutting the blank to the shape shown. Said tongue 19 has a straight end edge and inclined side edges.

The bits being made from sheet metal ermits the use of rolled stock. This ena les the bits to be initiall made of a-thickness conforming to the wi th of the kerfs or slots in screw heads without machining or other work to brin the bits to size. Being made of sheet meta the bits may be substantially uniform in strength throughout all portions of their length and width and thus be stronger than machine made hits as heretofore used, inasmuch as none of the strength of the stock is reduced in making the blts- The side flanges or lips 9, 9 reinforce the .bits against twisting and also hold the bits on screw heads when engaged therewith. This permits driving screws by power, increasing production, and savingtime and labor. Keeping the bits from slipping off the screw heads allows setting screws by power in finished work, as automobile bodies, furniture, etc., where hand methods have heretofore prevailed to prevent marring or injurin the work. Moreover, the bits being made rom sheet metal have substantially even thickness throughout and thus may be ground as they wear without altering the shape of the bits, thereby adding to the life of the same. Moreover, the bits being made in this way can be produced cheaply, which is a decided advantage.

While I have shown and described herein in detail sheet metal bits of m invention, it is of course to be understood hat the details of structure may be variousl changed and modified without departing rom the spirit and scope of my invention.

I claimas my invention:

1. A screw driving bit having a flat middle portion of a width and thickness to fit the slot or kerf in a screw-head, and havin integral flanges at its opposite longitudina edges to engage the outside of the screwhead at the ends of the slot or kerf therein, said flanges extending on opposite sides of said middle portion and curved to conform to the curvature of the screw-head.

2. In combination with a cylindrical holder having a longitudinal slot in its lower end, of a screw driving bit having a flat middle portion of a width and thickness to be secured at its upper end in the slot in said holder and to fit at its lower end in the slot or kerf of a screw-head, said middle portion having integral flanges along its opposite longitudinal edges to engage the outside of the holder and screw-head, respectively, at the ends of the slots therein, said flanges be ing curved to conform to the curvature of the holder and screw-head.

3. In combination with a holder having a longitudinal slot in its lower end, of a screw driving bit having a flat middle portion of a width and thickness to be secured at its upper end in the slot in said holder and to fit at its lower end in the slot or kerf in a screw-head, said middle portion having integral flanges extending on opposite sides thereof along its opposite longitudinal edges to engage the outside of the holder and screw-head, respectively, at the ends of the slots therein.

4. A screw driving bit having a flat mi'ddle portion of a width and thickness to fit the slot or kerf in a screw-head and to extend the full length thereof, said middle portion having integral flanges along its opposite longitudinal edges and continuing to the lower edge of said middle portion to engage the outside of the screw-head at the opposite ends of the slot therein.

5. A screw driving bit of sheet metal and having a flat middle portion of a width and thickness to fit the s otor kerf in a screwhead, and to extend the full length thereof, said middle portion having integral flanges extending on opposite sides thereof along the full length of 1ts opposite longitudinal edges to engage the outside of the screw-head at .opposite ends of the slot therein.

In testimony that I claim the foregoing as my invention, I aflix my signature, this 20th day of October, 1923.

' AXEL LEVEDAHL. 

